# QuickBooks could not be started Source: https://www.desktopaccountingapi.com/docs/help/connection-errors/cannot-start-quickbooks/ > Fix errors 0x80040408, 0x80040401, 0x80040424 and 0x8004042D when the Web Connector cannot start or reach QuickBooks Desktop. The Web Connector checked in, but it could not get QuickBooks Desktop running on the computer. There are two versions of this problem. One is a real failure to start, and the other means QuickBooks was still opening. ## What you see When QuickBooks could not start, the app shows: > QuickBooks Desktop could not start. Open QuickBooks and your company file on the computer that runs it, then try again. The Web Connector's **Last Result** column, or the app's support team, may show the code `0x80040408` or `0x80040401`. Through the Web Connector, `0x80040408` often means QuickBooks is open with a different company file, rather than that it failed to start. In that case the app says a different company file is open; see [A different company file is open](https://www.desktopaccountingapi.com/docs/help/connection-errors/wrong-company-file/). When QuickBooks was still opening, the app shows: > QuickBooks Desktop is still opening. Please try again in a minute. The matching codes are `0x80040424` and `0x8004042D`. During setup, the **Test the connection** step shows the title "QuickBooks could not start" or "QuickBooks is still starting". ## Why it happens When the app sends a request and QuickBooks is closed, the Web Connector tries to start QuickBooks in the background. That fails when: - QuickBooks is not installed for the Windows user who runs the Web Connector - QuickBooks is already starting, or is stuck partway through starting - QuickBooks and the Web Connector run at different permission levels, so they cannot see each other - several QuickBooks versions are installed, and the Web Connector picks the wrong one - QuickBooks is showing a startup message, such as an update or registration prompt, that needs someone to click it "Still opening" is different. QuickBooks was loading the company file when the request arrived. Large files take longer. This one usually clears up on its own. ## How to fix it 1. If the message says QuickBooks is still opening, wait a minute and try again in the app. Nothing else is needed unless it keeps happening. 2. On the computer that runs the Web Connector, open QuickBooks Desktop yourself and open the company file. Leave it open. If QuickBooks shows a message as it starts, read it and close it. 3. Try the action in the app again. If it works with QuickBooks open, the problem is QuickBooks starting in the background, so continue with the next steps to fix that for good. 4. Check how QuickBooks and the Web Connector start. If one runs with **Run as administrator** and the other does not, they cannot connect. See [Run QuickBooks and the Web Connector at the same permission level](https://www.desktopaccountingapi.com/docs/help/guides/run-as-administrator/). 5. Make sure only one QuickBooks Desktop version is installed. See [Keep one QuickBooks version installed](https://www.desktopaccountingapi.com/docs/help/guides/one-quickbooks-version/). 6. Check the setting you chose during setup. If you did not choose **Yes, always; allow access even if QuickBooks is not running**, QuickBooks has to stay open. See [QuickBooks denied access to the app](https://www.desktopaccountingapi.com/docs/help/connection-errors/access-denied/) to change it. 7. Restart the computer, sign in as the Windows user who set up the connection, open QuickBooks and the company file, then open the Web Connector. If QuickBooks itself will not open when you start it by hand, the problem is with the QuickBooks installation. Repair it from Windows **Settings › Apps** or with Intuit's repair tools, or ask your IT person. ## How to check it worked The app's action goes through. In the Web Connector, the app's row shows no error in **Last Result** after the next check-in. During setup, **QuickBooks opened the company file** ticks off. To test the background start, close QuickBooks, wait a minute, and use the app again. If it works, QuickBooks starts on its own when needed. ## When to contact the app's support Contact them if QuickBooks opens fine by hand but the error keeps coming back. Send the time, the exact message and code, which QuickBooks version and year you run, and a screenshot of the app's row in the Web Connector window. ## Related pages - [A QuickBooks window is blocking the connection](https://www.desktopaccountingapi.com/docs/help/connection-errors/modal-dialog-open/) - [Windows asks to allow this app to make changes](https://www.desktopaccountingapi.com/docs/help/connection-errors/windows-permission-prompt/) - [Start QuickBooks and the Web Connector at sign-in](https://www.desktopaccountingapi.com/docs/help/guides/start-automatically/) For developers, see [`QBD_CANNOT_START`](https://www.desktopaccountingapi.com/docs/errors/#qbd_cannot_start) and [`QBD_STARTING`](https://www.desktopaccountingapi.com/docs/errors/#qbd_starting).